What is the purpose of DCS, and how does it work?

May I ask whether data from the field conditions and those from the control platform need to be exchanged regularly? How often is “communication” carried out, generally? Furthermore, since “automated control” has been achieved, what do the actual people in the control room usually do?

It seems to be a newcomer indeed; just take a look around the factory and everything will become clear

All DCS systems have a CPU along with various other components such as IO cards and other accessories; these hardware elements are located within cabinets. In essence, their structure is similar to that of a computer. The IO cards regularly collect data from the field and send it to the CPU of the DCS system (commonly referred to as the main controller). The main controller then processes this data, carrying out tasks such as interlock control and PID control. The timing for data sampling and processing is determined by the hardware CPU, that is, the main controller. Each type of controller usually offers several different scanning periods, such as 50 ms or 500 ms, and users can customize these settings according to their own requirements during configuration. Currently, there is no system in the world that can operate entirely without human intervention and with 100% automated control; perhaps this will be possible in the future. Therefore, it is necessary for the personnel in the control room to monitor various situations that arise during the production process and to intervene manually so that production can proceed smoothly.

For DCS, you first need to understand the entire process; there are alarms for each control stage. Some pressures are monitored using level gauges, and it’s necessary to go to the site from time to time, but generally there are no problems. Doing this job on a long-term basis can be quite boring

Because there are not only control signals but also many signals that are merely for display, an operator is necessary. Even with automatic control, adjustments to set values and the like are still required, and human operation is needed.

In the control room, process operators typically monitor and manage various process parameters in real time. Automatic control is not a concept that applies to everything; only certain aspects are under automated control, while other elements still require manual intervention

It seems that the author is referring to a computer-based centralized control system, in which the signals for the actuators are generated by the computer; when the computer fails, the entire control system becomes dysfunctional； DCS is a distributed control system that evolved from centralized computer control. It is a multi-level computer system connected through communication networks, adopting a decentralized control, centralized operation, and hierarchical management approach; however, in the event of a failure in the central control room, it does not affect the normal operation of the various control points~~~

Thank you so much! But I didn’t understand—decentralized control, centralized operation. Someone mentioned to me \"centralized control,\" saying it’s difficult to manage, involves too many related factors, and is prone to problems. As for me, I actually still haven’t figured out how they work or what the differences are. Please give me some advice, I really need it!

Strictly speaking, it should be called “centralized management, decentralized control” – that way it will be clear! All the production process parameters on-site, including parameters such as temperature, pressure, flow rate, level, displacement, vibration, rotational speed, and other related process parameters, are converted into standard signals through various detection methods. These standard signals represent the values of these parameters and are transmitted to a centralized management system. This centralized management system can be a DCS or it can consist of a centralized control panel made up of conventional instruments, which is used by operators to monitor the production parameters. The system issues commands based on the process conditions and control criteria, enabling decentralized control of each individual process parameter in order to manage the overall production process.

What was said upstairs is absolutely true················